Mobile phone scam kills curious cats

NTT DoCoMo has been forced to introduce countermeasures to a mobile phone scam that is causing consternation in Japan.

The scam, which is known in Japanese as "wangiri" (one ring and cut), involves a computer using hundreds of phone lines to dial mobile phones numbers at random.

After one ring, the call hangs-up, which leaves the number stored in the receiving party's mobile phone.

If the person returns the call they are connected to a sales tape soliciting business, and sometimes sex, services and are usually charged at premium rates for the call by the subscriber at the other end.

Not only is the scam proving to be a major irritation for mobile phone users in Japan, but it is also disrupting business. Twice during August the phone lines in Osaka and the surrounding region have been jammed because of the scam.

Although one of NTT's regional subsidiaries has cut-off service to a company suspected of engaging in such activity, there is no legislation in Japan that makes the scam illegal.

In addition, NTT cannot release the names of businesses it suspects of being involved in the wangiri because of privacy legislation.

NTT DoCoMo had appealed to customers not to return calls from unknown numbers, but it appears that the allure of the mystery caller has proven stronger among the mobile-loving Japanese.

As a result, NTT DoCoMo said on Thursday that it was introducing a series of features over the coming months that it believes will thwart the efforts of the scammers.

The first of these is a new ring tone that remains silent during the first ring of an incoming call.

This, said DoCoMo, should mean that the customer's phone will not ring in the case of an incoming "wangiri" call. The download for the tone is to be made available sometime in September.

Another option put forward was for customers to use the "step-tone" feature that is already available in most DoCoMo phones. With "step-tone", the phone remains silent during the first ring, then gradually raises the ringing volume with subsequent rings.

In addition, DoCoMo said it will begin equipping phones with a feature that informs the customer of how long each incoming call rings for. It believes that this will help users determine if an incoming call from an unknown phone number might be a "wangiri" call. Phones equipped with the new feature will be made available in the autumn.

The final option from the mobile phone company is a service that allows users to register up to 19 "offending" telephone numbers on a dedicated network of DoCoMo.